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<H1>IBM Visualization Data Explorer Programmer&#39;s Reference</H1>
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<H3><A NAME="HDRDXNF" HREF="progu097.htm#PToC_345">DXNewField</A></H3>
<A NAME="IDX1912"></A>
<A NAME="IDX1913"></A>
<P><STRONG>Function</STRONG>
<P>
Creates a new Field Object.
<P><STRONG>Syntax</STRONG>
<BR>
<TT><STRONG><BR>
&#35;include &lt;dx/dx.h&gt;<BR>
<P><BR>
Field DXNewField()<BR>
</STRONG></TT><BR>
<P><STRONG>Functional Details</STRONG>
<P>
The Field Object is the fundamental Object in Data Explorer.
It consists of zero or more named components, usually Arrays, that are
accessed with <TT><STRONG>DXGetComponentValue</STRONG></TT> or
<TT><STRONG>DXGetEnumeratedComponentValue</STRONG></TT>.
Initially, the Field has no components and is said to be empty;
<TT><STRONG>DXEmptyField</STRONG></TT> returns "1" for
such Fields.
Components are inserted in the Field using the function
<TT><STRONG>DXSetComponentValue</STRONG></TT>.
<P>
There are several predefined component names in Data Explorer.
The component "positions" generally refers to the points in the
data space where the field is sampled; "connections" are
the relationships between the "positions" and their
interpolation; "data" refers to the values either
at the "positions" or for each whole
"connections" element.
<P>
The Field created can be deleted with DXDelete.
See <A HREF="progu023.htm#HDRMEMNG">4.2 , "Memory Management"</A>.
<P>

Note that certain attributes on the components on a field are necessary
for proper processing of the field. For example, a "connections"
component must "ref" the "positions" component, and the
"data" component must "dep" either the "positions" or
"connections" component (see <A HREF="usrgu025.htm#TBLCOMPATT">Table 2</A> in
<I>IBM Visualization Data Explorer User&#39;s Guide</I>,
and <A HREF="progu022.htm#HDRDATAM">4.1 , "Data Explorer Data Model"</A>).
<P>
It is recommended that DXEndField be called on any field created when
you are finished adding components to it. DXEndField trims away
allocated but unused space in the component arrays, and will in
addition, set some default component attributes. See <A
HREF="progu136.htm#HDRDXENDF">DXEndField</A> for more information.

<P>
See <A HREF="usrgu024.htm#HDRDATMOD">Chapter 3. "Understanding the Data
Model"</A> in
<I>IBM Visualization Data Explorer User&#39;s Guide</I> for additional
information on the Data Explorer data model.
<P><STRONG>Return Value</STRONG>
<P>
Returns the Field or returns <TT><STRONG>NULL</STRONG></TT> and
sets an error code.
<P><STRONG>See Also</STRONG>
<P>
<TT><STRONG>
<A HREF="progu135.htm#HDRDXEMF">DXEmptyField</A>,
<A HREF="progu163.htm#HDRDXGCV">DXGetComponentValue</A>,
<A HREF="progu168.htm#HDRDXGECV">DXGetEnumeratedComponentValue</A>,
<A HREF="progu307.htm#HDRDXSCV">DXSetComponentValue</A>
</STRONG></TT>
<P>
<A HREF="progu044.htm#HDRFIELDSC">12.1 , "Field Class"</A>.
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